Sound-record.



L. C. HAHN.

SOUND RECORD.

APPLICATION FILED APR. 16. 1913.

Patented May 30, 1916.

Inventor Witnesses Attorneys LAURA c. HAHN, or sTUneEoN BAY, WISCONSIN.

SOUND-RECORD.

Specification-of Letters Patent.

Patented May 30, 1916.

Application filed April 16, 1918. Serial No. 761,444.

To all whom it may concern Be it known that I, LAURA CooHEMs HAHN, a citizen of the UnitedStates, residing Door and State of Wisconsin, have invented a new and useful Sound-Record, of which the following is a specification.

In the tuning of a pianoforte, or similar keyed musical mstrument, to produce equal temperament,v it is necessary that the tone intervals, namely, thirds, fourths, fifths and sixths, shall bear certain relations to each other, not only with reference to pitch, which is determined bythe frequency and length of sound vibrations of the respective tones but with reference to the frequency and length of beats or waves of sound which are distinguishable by the human ear, and which are due to the simultaneous occurrence or agreement at intervals of certain vibrations constituting said tones, or, as they may be termed the nodal points of the two tones forming the particular tone interval which is being sounded.

By taking advantage of the fact that these beats, which are distinguishable to the ear when a given tone interval is sounded, must have a certain frequency in order to produce in the completed circle an equal temperament it is possible to tune the circle of a keyed instrument by progressively sounding and justifying the tone intervals, and it is the object of my invention to provide a device by means of which these several tone intervals are sounded, or may be reproduced consecutively in the proper order of progression through the circle, to serve as a definite and invariable guide to the tuner of a musical instrument.

Assumin a pitch for small E and sound ing therewlth small C, major third below, the beats perceptible to the ear should agree with the ticks of an ordinary good movement watch, while said E sounded with small G sharp above, should produce beats at the rate about one-third faster. With one-lined O tuned smooth or without perceptible beat with small G, and tested with G- sharp the tenth below one-lined and which, if correct, will be smooth or without perceptible beat, there is established a basis for the further tuning of. the circle, wherein the tone interval G sharp-0ne-lined C will produce a beat one-third faster than the tone interval small EG sharp.- The inter-v val small 0 sharp-G sharp, in practice,

at Sturgeon Bay, in the county of should then be tuned a smooth or perfect fifth, so that the tone intervals small C sharpE will beat the same as small EG sharp, andthen this fifth should be contracted by raising small C sharp to an extent suificlent to cause a two-beat reduction in the interval small 0 sharpE, as comcontracting the fifths and expanding the.

fourths, a circle of equal temperament can be produced. In carrying out my invention, I have prepared a sound record having means, such as I grooves, indentations or undulations, adapted when in use to reproduce respectively and consecutively thesetone intervals, as for example, small C and E, small E and G sharp, small G sharp (or A flat) and C, small C and one-lined C (octave) with lower G sharp (tenth), small 0 shar and G sharp, small C sharp and E, small E and G sharp,

small G and F, small 0 shar and F, and so on through the circle, each 0 the tone intervals as reproduced representing-the correct frequene of beats for the guidance of the tuner. he record of these tone intervals, or the grooves, indentations or undulations of the sound record may be producedin any suitable or well known manner, as by recording devices of any of the well .known types, exposed successively to sustained productions of the respective tone intervals produced by any instrument, or combination of instruments, tuned tothe proper temperament, and in. the accompanying drawing there is shown in- Figure 1 apho'nographic record cylinder wherein appear record grooves, each of which extends continuously around the cylinder, and each of which represents a given tone interval, whereby, when the needle of -a reproducer is actuated thereby, the corresponding tone interval is sounded; Fig. 2a

diagram of a portion of a chart representing certain of the tone intervals represented by the record. V

In practice, it 1s only necessary 'to ad- I 7 just the speed of rotation of the record, to

produce the desired pitch of sound for small octave E of the initial tone interval, after which the consecutive use of the tone records will result in a reproduction of the several tone intervals occurring in the circle, and after the completion of the circle, the instrument under manipulation can be tuned therefrom in both directions as to octaves, which, as in the ordinary instrument, may be shaded more or less to give the desired brilliancy to the upper registers and sonority to the lower registers.

What is claimed is:

1. A sound record adapted to assist in tuning pianofortes or similar keyed musical instruments which employ the modulated or equally tempered scale having audible representations of the tone intervals in the pro er order of progression followed in 'tunmg the instrument to the modulated or equally tempered scale.

2. A' sound record ada ted to assist in tuning pianofortes or sim' ar keyd musical instruments which employ the modulated or equally tempered scale having audible representations of the modulated tone intervals in the proper order of progression followed in tuning the instrument to the modulated or equally tempered scale.

3. A sound record adapted to assist in tuning pianofortes or similar keyed musical instruments which. employ the modulated 'or equally tempered scale having audible representations of the modulated tone intervals corresponding in Wave frequency with the same tone intervals followed in tuning the instrument to the modulated or equally tempered scale.

4. A sound record adapted to assist in tuning pianofortes or similar keyed musical instruments which employ the modulated or equally tempered scale having audible representations in proper consecutive succession of the tone intervals sounding the pitch to be tuned and certain of its harmonic overtones, the succession of tone intervals audibly represented by the sound record constituting the circle of the tone intervals employed 1n tuningthe instrument to the modulated or equally tempered scale, substantially as described.

In testimony that I claim the foregoing as my own, I have hereto aed my signature in the presence of two witnesses.

LAA 0. 

